This article is from the Recreational Figure Skating FAQ, by Karen Bryden with numerous contributions by others.
The blade length denotes the measurement from the front of the sole
plate to the back of the heel plate. Measure the length of the sole
from toe to heel and fit blades which are 1/4 inch less in length.
Some people believe that they have to buy blades that are super
expensive in order for them to become great skaters. You should buy
well-built and *appropriate* equipment. Skaters gradually upgrade
their equipment as their needs change, for example a skater may need
to upgrade skates when they move from basic skating to their first
jumps or from double to triple jumps. Advanced blades require the
skater to perfect his/her technique.
Top of the line blades are designed for very advanced skaters.
Advanced free-style blades have a longer radius and have *large* toe
picks. Also, the portion of the blade that is used for spinning is
much shorter than on intermediate blades; that means that unless you
are perfectly balanced and positioned going into and during the spin
you will start rocking on the blade. Intermediate blades like the MK
Professional, Coronation Ace, etc. provide you more "room" to make
corrections and continue spinning even if you are slightly off
Just because the MK Gold Stars are typically over $400 does not mean
that they are inherently better blades than MK Pros or Phantoms.
Starting with MK Pro and Coronation Ace lines, the blades are all made
using much the same materials and manufacturing process as described
above. To put it succinctly, certain blades are more expensive simply
because of supply and demand and a few slight design modifications
like side honing which makes them marginally more costly to produce.